Yasuhiro Okuda

Transition-metal catalyzed silylzincation and silylalumination of acetylenic compounds

Abstract Dialkyl(dimethylphenylsilyl)zinclithium and trialkyl(dimethylphenylsilyl)aluminiumlithium add effectively to internal acetylenes as well as terminal ones in the presence of transition-metal catalysts to provide vinylsilanes with high stereo- and regioselectivities.

Intramolecular cyclization mediated by silylmetalation of acetylenes with PhMe2SiMgMe/CuI and radical nature of the reagent

Abstract Whereas CuI catalyzed silylmagnesation of the tosylate of 5- hexyn-l-ol with the title reagent affords dimethylphenylsilylmethylenecyclopentane exclusively, the mesylate of 3-butyn-l-ol gives a mixture of unexpected silylcyclobutene and cyclopropylidene derivative.

Copper catalyzed silylzincation of acetylenes

Abstract Dialkyl(dimethylphenylsilyl)zinclithium adds effectively to internal acetylenes as well as terminal acetylenes in the presence of CuCN catalyst.

New synthesis of allylsilanes and vinylsilanes by means of PhMe2Si-AlEt2

Abstract The reaction of allylic phosphates with the title organoaluminium reagent (PhMe 2 Si-AlEt 2 ) provides allylsilanes in good yields. Cross coupling of enol phosphates with PhMe 2 Si-Mtl (Mtl = AlEt 2 or MgMe) produces vinylsilanes regio- and stereoselectively in the presence of Pd(0) catalysts.

β,β‐Diborylated Subporphyrinato Boron(III) Complexes as Useful Synthetic Precursors

Iridium-catalyzed borylation of B-aryl meso-free subporphyrinato boron(III) complexes (hereinafter referred to simply as subporphyrins) with bis(pinacolato)diboron gave 2,13-diborylated subporphyrins regioselectively, which served as promising synthetic precursors for 2,13-diarylated subporphyrins and doubly β-to-β 1,3-butadiyne-bridged subporphyrin dimers. 2,13-Diarylated subporphyrins display perturbed absorption spectra, depending upon the β-aryl substituents. Doubly 1,3-butadiyne-bridged syn and anti subporphyrin dimers thus prepared exhibit differently altered absorption spectra with split Soret-like bands, which have been accounted for in terms of exciton coupling.

A meso–meso β‐β β‐β Triply Linked Subporphyrin Dimer

A meso-meso β-β β-β triply linked subporphyrin dimer 6 was synthesized by stepwise reductive elimination of β-to-β doubly PtII -bridged subporphyrin dimer 9. Dimer 6 was characterized by spectroscopic and electrochemical measurements, theoretical calculations, and picosecond time-resolved transient absorption spectroscopy. X-ray diffraction analysis reveals that 6 has a bowl-shaped structure with a positive Gaussian curvature. Despite the curved structure, 6 exhibits a remarkably red-shifted absorption band at 942 nm and a small electrochemical HOMO-LUMO gap (1.35 eV), indicating an effectively conjugated π-electronic network.